Hockey stick with plastic wear strip

ABSTRACT

The hockey stick has a plastic wear strip along the bottom edge of the blade of the stick. Preferably the wear strip is of polyurethane having a flexural modulus in the range of 300 to 550 MPa at room temperature and 1200 to 1400 MPa at −30 degrees Celsius. In a goaltender&#39;s stick having a foam core, the wear strip is inserted in a mold and integrally formed with the core of the stick. The wear strip preferably is manufactured via a RIM process, then the core of the stick is molded with the wear strip and stick shaft in position, and then conventional finishing steps are applied, with fiberglass overlays for example.

BACKGROUND OF THE INVENTION

This invention relates to the sport of hockey, and in particular tohockey sticks. The invention is especially applicable to goalie sticks,i.e. the sticks used by hockey goaltenders, but it is conceivable thatthe invention could be adapted to hockey sticks generally.

Hockey sticks, including goalie sticks, are subject to a good deal ofabuse in recreational use, practices and games. Furthermore, modernhockey sticks are significantly more expensive than traditional woodensticks, due to the materials used and the amount of labor involved intheir manufacture. This is particularly the case with goalie sticks, dueto the smaller volumes produced and due to their somewhat more complexoverall structure.

Normal hockey sticks tend to break mostly during slap shots, from impactwith the hockey puck or the ice surface or both. They may also breakfrom other impacts, for example with the hockey boards, goalposts, orfrom deliberate breakage by frustrated players. Goalie sticks are lessprone to breakage from impact, primarily because impacts are lessfrequent. However, they can also be broken deliberately by a frustratedgoaltender. Otherwise, the primary cause of deterioration of thestructural integrity of the stick is wear of the blade of the stick dueto friction between the bottom of the stick and the ice, in combinationwith constant puck impacts and force applied by the goaltender towardsthe surface of the ice. Wear from these factors becomes a significantfactor in determining the life of the stick. Delamination or otherproblems may arise. When a stick blade is starting to delaminate, thequality of puck deflection is not consistent and cannot be properlycontrolled by the goaltender. The longer period of time that the bladeremains intact, the more consistent its characteristics are, and thelonger players are able to use it with good results.

In view of the preceding, it would therefore be advantageous to have agoalie stick design which extends the life of the stick for as long aspossible, by reducing wear of the blade. Such a design might also bereadily adaptable to normal hockey sticks, to potentially extend theirlife as well.

BRIEF SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide a hockey stickwith improved durability. For convenience, generally only a goalie stickwill be described herein, but as mentioned above, the inventionconceivably could be adapted to other hockey sticks.

In the invention, a plastic wear strip is embedded along a bottom edgeof the blade. Preferably, the plastic strip is a somewhat flexiblepolyurethane strip, and extends a substantial distance along the bottomof the blade. More preferably, the plastic strip extends substantiallythe full length of the hockey stick blade, from heel to toe.

Preferably, the wear strip is somewhat flexible (at least prior toinstallation), durable, abrasion resistant, and capable of absorbingenergy when impacted. Preferably, in the case of a foam core stick, thewear strip has chemical affinity, i.e. it is chemically similar to thecore material of the stick. Its contribution to the reboundcharacteristics of the stick ideally should be neutral.

In a preferred embodiment, the wear strip is manufactured in atwo-component polyurethane reaction injection molding (RIM) system, andhas a flexural modulus of preferably about 500 MPa at room temperatureand preferably about 1300 MPa at −30 degrees Celsius.

From testing, this wear strip appears to have the ability to absorbimpact forces and therefore appears to prolong stick life by insulatingthe foam core material from those impact forces. However, it isconceivable that other urethane materials, whether using the RIM processor injection molding, could be acceptable for use. That could bedetermined by routine testing and experimentation.

Further details of the invention will be described or will becomeapparent in the course of the following detailed description anddrawings of specific embodiments of the invention, presented as examplesonly.

BRIEF DESCRIPTION OF THE DRAWINGS

Specific embodiments of the invention will now be described, by way ofexample only, with reference to the attached drawings, in which:

FIG. 1 is a perspective view of a preferred embodiment of a hockeygoaltender's stick, with a wear strip along the bottom edge of the bladeand part of the heel;

FIG. 2 is a side view of the wear strip;

FIG. 3 is a cross-section of the wear strip at A-A of FIG. 2;

FIG. 4 is a similar cross-section, showing an alternative configurationfor the web portion of the wear strip; and

FIG. 5 is another similar cross-section, showing another alternativeconfiguration for the web portion of the wear strip.

DETAILED DESCRIPTION OF THE INVENTION Structure

A preferred embodiment of the invention is illustrated in FIG. 1, whichshows a goalie stick 1. The stick has a core 2 and a shaft 3 which isembedded in the core as part of the core molding process, as describedin more detail below. The goalie stick has a paddle portion 4, and ablade 5, both of which are integral parts of the core 2. The blade has aheel 6 and a toe 7. In the case of a regular hockey stick, there is ofcourse no paddle; the shaft extends all the way down to the blade.

Embedded along the bottom edge of the blade 5, preferably but notnecessarily running its full length from the heel to the toe, is aplastic wear strip 8 according to the invention, as shown in FIGS. 1-3.The wear strip is shaped to follow the shape of the bottom of the blade,and preferably an upwardly-rising portion of the heel. The wear strip ismade of a somewhat flexible and preferably somewhat resilient plastic,preferably polyurethane. Dimensions shown in FIGS. 2-3 are typical, butobviously could be varied.

The flexibility of the wear strip 8 is sufficient at least to faciliateits positioning in the mold and its use with somewhat different bladeshapes, since there can be a wide variety of shapes. The flexibilityalso allows for the blade to be curved, without any undue or permanentstress which would negatively impact on the stick's usable life.

The wear strip preferably also has some resilience, which cushionsimpacts slightly, i.e. absorbs energy, thus reducing the transfer ofenergy to the main body of the blade 5 and core 2. This cushioningeffect extends the life of the stick more than if the strip was a rigidplastic piece.

In a preferred embodiment, the core 2 is a polyurethane foam andfiberglass structure, as is presently conventional, having a flexuralmodulus of 300-550 MPa at room temperature. The wear strip materialshould adhere suitably to the foam with a strong permanent bond, andshould accept being bonded to the typical fiberglass outerreinforcements of the stick.

As seen best in FIG. 3, the wear strip 8 preferably is generally in theshape of an inverted “T”, such that its bottom portion 9 covers thewidth (i.e. thickness) of the bottom edge of the blade, and itsupwardly-extending web portion 10 extends into the blade core and isanchored therein.

Preferably, the web portion 10 has a number of holes 11 through it, sothat the foam expands into those holes for more secure anchoring of theweb portion and wear strip generally. Instead of holes, the web portioncould be provided with other means for anchoring, such as by providingribs 12 and/or slots 13, as seen in FIG. 4, or zig-zag shapes 14 as seenin FIG. 5, or protruding pins (not shown), or any other suitable means.

Wear Strip Material

In selecting the material for the wear strip 8, it was desired to have amaterial which would be compatible with the core of the blade, to adhereto it so as to form an integral and strong unit, enhance the finalquality of the core, and increase the durability of the total stick byprotecting the bottom part of the core from abrasion against the ice,without unduly affecting rebound characteristics of the core. It wasalso desired to have a material which would be technologically easy toproduce, by molding for example, instead of machining from a plasticsheet. Ideally the material would have similar mechanicalcharacteristics to the core and be chemically compatible with the core.

As mentioned in the summary above, in a preferred embodiment, the wearstrip is manufactured in a two-component polyurethane reaction injectionmolding (RIM) system, and has a flexural modulus of preferably about 500MPa at room temperature and preferably about 1300 MPa at −30 degreesCelsius. A RIM system is preferred due to the lower mold and materialcosts compared to injection molding. However, a thermoplasticpolyurethane material could instead be selected and injection molded toproduce the wear strip.

In this RIM process, two components are delivered separately to a mixinghead by high pressure pumps and are mixed under very high pressure. Theresulting mixture is injected from the head into a closed mold, wherethe chemical reaction between the components forms rigid thermoplasticpolyurethane. The result is a product which has a flexural modulus lessthan most other polymers (such as polyethylene, polypropylene, Nylon,etc.), but which is strong enough to permit significant part deformationwithout damage. The RIM process also is technologically suitable forprocessing, allowing faster demolding times (between 40 seconds and 2minutes for example), and providing good flow characteristics to fillthe mold quickly and easily to produce a high quality part without airbubbles or distortion. The resulting product has to pass low temperatureflexural modulus testing and should not be brittle enough to break attemperatures as low as −30 Celsius or even −50 Celsius.

The polyurethane system for the wear strip 8 was chosen to be as closeas possible to the existing core materials while still achieving thegoals of the invention. The selected polyurethane system produces a wearstrip with flexural modulus generally in the same range as the core, andeven more importantly, does not break at −30 Celsius or even lower. Intesting, the flexural modulus at −30 Celsius was in the range of 1,200to 1,400 MPa, and the wear strip did not break. The material has a hardand durable surface with a Shore A durometer reading of preferably butnot necessarily at least 80, and better still preferably 90 to 95, withalso high abrasion resistance.

Process

In manufacturing the stick as a whole, there are three main steps. Thefirst step is manufacturing the wear strip, preferably but notnecessarily via the RIM process as described above. The second step ismolding the core of the stick, with the wear strip 8 and shaft 3embedded in it. The third step is finishing the stick. The second andthird steps are essentially conventional, with the exception that thewear strip is positioned in the mold for the core, so as to be capturedalong the bottom edge of what becomes the blade of the stick.

In the core molding process, typically a fiberglass mat is laid into thecavity of a clamshell mold. The wear strip 8 of the invention is thenpositioned along the edge of the cavity corresponding to the bottom ofthe blade 5. The shaft 3 is also positioned so that its lower end willbe captured by the core material. The shaft could be wood, laminatedplywood, a solid core with veneer, a composite material, or any othersuitable material. The composition of the shaft is not part of theinvention.

Then typically a spacer is placed in the mold, and the spacer isoverlaid with another fiberglass mat. The fiberglass mats constitute theouter surfaces of the core, and the spacer holds them in their properpositions prior to injection of the foam.

The mold is closed, a dispensing head is positioned over the mold inlet,and the dispenser is activated to introduce a conventional two-componentpolyurethane foam resin system into the mold. The foam fills the moldcavity, and also surrounds the web portion 10 of the wear strip 8, toanchor it in place. After curing, the mold is opened, the core 2 isdemolded (with the wear strip 8 and shaft 3 captured), flash is trimmedoff and the part is inspected for defects.

It should be understood that these details of the molding process,except for the insertion of the wear strip, are generally conventionaland not part of the invention.

Once the reaction is complete and the mold is opened, the result is acompleted core of foam overlaid with fiberglass, with the wear stripsecured along the bottom edge of the blade, and the hockey stick shaftextending out the upper end of the core. The stick is now ready forfinishing operations. These finishing operations are conventional, andtherefore will not be described in detail, but may include removal ofexcess flash, sanding, applying additional layers of fiberglass orcarbon fiber, bending the blade to a desired finished shape, andapplying finish coats of paint or urethane coat, along with appropriatebranding or other graphics.

CONCLUSION

It will be evident to those knowledgeable in the field of the inventionthat many variations on the examples described above are conceivablewithin the scope of the invention. It should therefore be understoodthat the claims which define the invention are not restricted to thespecific examples described above.

The hockey stick may not necessarily have a polyurethane foam core. Forexample, it could be made of a number of other thermoplastic foams, withthe wear strip 8 having any complementary shape and being positionedalong the bottom edge, held in place by a fiberglass wrap during themanufacturing process, or by an adhesive.

Further variations may be apparent or become apparent to thoseknowledgeable in the field of the invention, within the scope of theinvention as defined by the claims which follow.

1. A hockey stick, having a blade with a toe end and a heel end, whereina plastic wear strip is positioned along a bottom edge of the blade. 2.A hockey stick as in claim 1, where the plastic wear strip is of asomewhat flexible and somewhat resilient polyurethane.
 3. A hockey stickas in claim 2, where the polyurethane has a flexural modulus in therange of 300 to 550 MPa at room temperature and 1200 to 1400 MPa at −30degrees Celsius.
 4. A hockey stick as in claim 1, wherein the wear stripis embedded in bottom of the blade.
 5. A hockey stick as in claim 4,where the plastic wear strip is of a somewhat flexible and somewhatresilient polyurethane.
 6. A hockey stick as in claim 4, where thepolyurethane has a flexural modulus in the range of 300 to 550 MPa atroom temperature and 1200 to 1400 MPa at −30 degrees Celsius.
 7. Ahockey stick as in claim 1, configured as a goaltender's stick andhaving a polyurethane foam core comprising said blade, wherein the wearstrip is molded integrally with said foam core so as to be captured bysaid foam core.
 8. A hockey stick as in claim 7, wherein said wear striphas a projecting central web portion, and wherein said web portion iscaptured by said foam core to hold said wear strip in position.
 9. Ahockey stick as in claim 8, where the plastic wear strip is of asomewhat flexible and somewhat resilient polyurethane.
 10. A hockeystick as in claim 9, where the polyurethane has a flexural modulus inthe range of 300 to 550 MPa at room temperature and 1200 to 1400 MPa at−30 degrees Celsius.